LM1 was discovered in 1969 and is one of the world's oldest known cremations.[1][3] LM3, discovered in 1974, was an early human inhabitant of the continent of Australia, who is believed to have lived between 40,000 and 68,000 years ago, during the Pleistoceneepoch. The remains are the oldest anatomically modern human remains found in Australia to date. His exact age is a matter of ongoing dispute.

LM1 was discovered in 1969 in the Willandra Lakes Region by Jim Bowler with the University of Melbourne.[4] LM1 has been 14C dated at 24,700 to 19,030 years ago. A date of 26,250 ±1120 BP was achieved with charcoal from a hearth 15 cm above the burial.[5] Preservation of the remains is poor. Very limited detailed information was published before the bones were unconditionally "repatriated" to the Indigenous people of Australia in 1992. A lack of a detailed description of the remains along with a limited distribution of casts with no access to the original artifacts makes it difficult to assess the published material.[5]

It represents one of the world's oldest known cremations. The finding implies that complicated burial rituals existed in early human societies.

The pattern of burn marks on the bones of LM1 is thought to imply that after she died, the corpse was burned, then smashed, then burned a second time before being liberally covered with ochre sourced from a location several hundred kilometers from the site. One suggested explanation for this behaviour is that the process was perhaps a ritual wherein the descendants try to ensure that the dead did not return to haunt them.

The bones were unconditionally repatriated in 1992 to the traditional owners, an alliance called the Three Traditional Tribal Groups (3TTG), consisting of the Paakantji, the Mathi Mathi, and the Ngiyampaa. LM1 had become a symbol of the long Aboriginal occupation in Australia, and an important icon for both archaeologists and indigenous Australians. LM1 is now in a locked vault at the Mungo National Park exhibition center. The vault has a double lock and can only be opened if two keys are used. One key is controlled by archaeologists, the other by the local indigenous peoples.

Lake Mungo 3 (LM3) was discovered by ANU geomorphologist Dr. Jim Bowler on 26 February 1974 when shifting sand dunes exposed his remains.[6] He was found near Lake Mungo, one of several dry lakes in the southeast part of the continent and 500m east of the LM1 site. The body was sprinkled with red ochre, in the earliest known example of such a sophisticated and artistic burial practice. This aspect of the discovery has been particularly significant to indigenous Australians, since it indicates that certain cultural traditions have existed on the Australian continent for much longer than previously thought.

The skeleton was of a gracile individual, which contrasts with the morphology of modern indigenous Australians.[7] The skeleton had been somewhat poorly preserved, with substantial portions of the skull missing, and most of the bones in the limbs suffering surface damage. The skull and pelvis bones carry many features used to determine sex, and with most of those features unavailable in LM3, determination of sex has been difficult. Nevertheless, significant studies of other diagnostic features since its discovery have reached a relative consensus around the remains being those of a male.[8][9][10]

LM3 was buried lying on its back, with his hands interlocked covering the groin. Based on evidence of osteoarthritis in the lumbar vertebrae, eburnation, and severe wear on the teeth with pulp exposure, it seems likely that LM3 was quite old (around 50 years old) when he died.[11] New studies show that, using the length of his limb bones, it is possible to estimate LM3's height at 196 centimetres (77 inches or 6 ft 5 in), abnormally tall for an Aboriginal.[12]

The first estimate of LM3's age was made in 1976, when the team of paleoanthropologists from the Australian National University (ANU) who excavated LM3 published their findings. They estimated that LM3 was between 28,000 and 32,000 years old.[6] They did not test LM3's remains directly, but rather established an estimate by stratigraphic comparison with LM1, an earlier set of partially cremated remains also found at Lake Mungo.

In 1987, an electron spin resonance test was conducted on bone fragments from LM3's skeleton, which established an estimate of his age at 31,000 years, plus or minus 7,000 years. In 1999 Thermoluminescence dating work was carried out on quartz from unburnt sediment associated with the LM3 burial site with the selective bleach results indicating a burial older than 24,600 ± 2,400 and younger than 43,300 ± 3,800 years ago.[13] Later Thorne et al. (1999), arrived at a new estimate of 62,000 ± 6,000 years. This estimate was determined by combining data from uranium-thorium dating, electron spin resonance dating and optically stimulated luminescence (OSL) dating of the remains and the immediately surrounding soil.[14]

However, this estimate was very controversial.[15][16][17] The lowest level of the LM3 which are as old as 43,000 years demonstrated that LM3 should not be older than the lowest layer. However, the ANU team had dated the stratum itself to be between 59,000 and 63,000 years old. The problems with using uranium-thorium dating on tooth enamel was criticized. The results from 25 additional OSL tests suggests that LM3 can not be older than 50,000 years BP. According to anthropologist Peter Brown, with the absence of the original deposit that once lay above the burial, a minimum age for the burial has not been established, only a possible maximum.[11]

In 2003, collaboration of several Australian groups reached a consensus that LM3 is about 40,000 years old.[18] This age largely corresponds with stratigraphic evidence using 4 different dating methods. The age of 40,000 years is currently the most widely accepted age for the LM3, making LM3 the second oldest modern human fossil east of India. The study also found that LM1 was a similar age to LM3, and not 30,000 years old, as previously thought.[19] The LM1 remains are generally held to be the earliest evidence of human cremation yet discovered. [20]

The current mainstream thinking, the recent African origin of modern humans model, suggest that all humans alive today descended from a small group, which left Africa at a specific time, currently generally estimated at about 60,000 years ago. This estimate of 60,000 years is arrived at from the recent breakthrough of widespread genetic investigation. In the model, humans then fairly quickly spread over the whole globe, from that starting point or bottleneck (indeed, with Australia being perhaps the furthest, most difficult to reach, area).

This explains the controversy of Thorne and other's older dates for LM3 - the establishment of (fully modern) human settlements in the different continents, could only have happened after (although perhaps remarkably shortly after) the exodus of the original (perhaps remarkably small) group of humans who left Africa via the middle-East.

In 2001, mitochondrial DNA (mtDNA) from the Lake Mungo 3 (LM3) skeleton was published and compared with several other sequences. It was found to have more than the expected number of sequence differences when compared to modern human DNA (CRS). A portion of the mtDNA of LM3 survives in modern humans as a segment found in chromosome 11.[21]

The divergence of the LM3 sequence before the MRCA of contemporary human sequences is indicated by its grouping with the Insert sequence (Fig. 1B), which other reports have suggested diverged before the MRCA of sequences in living humans

Comparison of the mitochondrial DNA with that of ancient and modern Aborigines has indicated that Mungo Man is not related to Australian Aborigines. The results indicated that Mungo Man was an extinct subspecies that diverged before the most recent common ancestor of contemporary humans. These results, if correct, may support the multiregional origin of modern humans hypothesis.[21][22]

These claims are both scientifically and politically controversial and have been met with a general lack of acceptance in scientific communities, the sequence is criticized as there has been no independent testing and some of these differences may be due to posthumous modification and thermal degradation of the DNA.[23][24][25][26][11] Authentication tests need to be performed before the results can be accepted but further testing is unlikely as the indigenous custodians, the Paakantji, the Mathi Mathi, and the Ngiyampaa, are not expected to allow further invasive investigations.[27]

In 1988, the skeleton of a child believed to be contemporary with Mungo man was discovered. Investigation of the remains was blocked by the 3TTG with the remains subsequently protected but remaining in-situ.[28] An adult skeleton was exposed by erosion in 2005 but by late 2006 had been completely destroyed by wind and rain. This loss resulted in the indigenous custodians receiving a government grant of $735,000 to survey and improve the conservation of skeletons, hearths and middens that were eroding from the dunes. Conservation is in-situ and no research is permitted.[29]